Calcium oxide, commonly known as quicklime or burnt lime, is a white, alkaline, and crystalline solid. It is produced by heating limestone (calcium carbonate) in a process called calcination, which releases carbon dioxide. Calcium oxide is highly reactive and can absorb moisture from the air, forming calcium hydroxide, also known as slaked lime. This compound has various applications, including in the construction industry for making cement and mortar. It is also used in the production of glass, as a pH regulator in water treatment, and in agriculture to improve soil quality.